1656666320 has 80 divisors (see below), whose sum is σ = 4088912400. Its totient is φ = 622067712.

The previous prime is 1656666313. The next prime is 1656666353. The reversal of 1656666320 is 236666561.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 336942736 + 1319723584 = 18356^2 + 36328^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 609284 + ... + 611996.

It is an arithmetic number, because the mean of its divisors is an integer number (51111405).

Almost surely, 2^1656666320 is an apocalyptic number.

1656666320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1656666320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2044456200).

1656666320 is an abundant number, since it is smaller than the sum of its proper divisors (2432246080).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1656666320 is a wasteful number, since it uses less digits than its factorization.

1656666320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3192 (or 3186 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 41.

The square root of 1656666320 is about 40702.1660357284. The cubic root of 1656666320 is about 1183.2549983631.

The spelling of 1656666320 in words is "one billion, six hundred fifty-six million, six hundred sixty-six thousand, three hundred twenty".